This submenu key shows the current value for span in units of GHz, MHz, kHz, or Hz. When the Span button is pressed, span becomes the active parameter and may be changed. Use the keypad, the directional arrow keys, or the rotary knob to increase or decrease the span frequency. If the span is changed using the arrow keys, the span changes in a 1-2-5 sequence for each key press.
This is a convenient way to quickly arrive at a wider span value. The first time the submenu key is pressed, the span value increases to the nearest even value that starts with 1, 2, or 5. For example if the span is 1.8 MHz, pressing the submenu key for the first time changes the span to 2.0 MHz, the next press takes the value to 5.0 MHz and so on.
This is a convenient way to narrow the frequency span. The first time the submenu key is pressed, the span value decreases to the nearest even value that starts with 1, 2, or 5. For example if the span is 1.8 MHz, pressing the submenu key for the first time changes the span to 1.0 MHz, the next press takes the value to 500 kHz, then 200 kHz and so on.
This submenu key sets zero span. In this mode the display shows amplitude changes at a single frequency. This function is frequently used to allow the easy monitoring of power variations over time. For example, if information about the amplitude of an 802.11a access point signal is needed, the access point frequency would be set as the center frequency, resolution bandwidth would be set to a value wide enough to encompass as much of the signal as possible and the tester would walk around the access point usable area while the instrument records the amplitude using slow sweep.
Zero Span IF Output provides a 140 MHz IF signal out of a BNC female connector. The IF output signal is present only when the instrument span is set to zero. The user can select the one of four fixed IF bandwidths 7 MHz, 10 MHz, 16 MHz, or 32 MHz in addition to the bandwidths set by the instrument’s RBW filters. When Normal is selected, the IF bandwidth is influenced by the RBW filters and can be any value from 1 MHz to 1 Hz. The exact bandwidth is wider than the selected RBW filter. This is not the suggested way to use IF output.
